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3 years ago

Plz help me with it

Mathematics

2 answers:

Radda [10]3 years ago

8 0

<h3>5 should be the answer I hope</h3>

Morgarella [4.7K]3 years ago

8 0

Answer: 5

<u>Step-by-step explanation:</u>

$\sqrt{4x+5}-\sqrt{x-1}=\sqrt{x+4}\\\\(\sqrt{4x+5}-\sqrt{x-1})^2=(\sqrt{x+4})^2\\\\4x+5-2\sqrt{(4x+5)(x-1)}+x-1=x+4\\\\5x+4-2\sqrt{(4x+5)(x-1)}=x+4\\\\4x=2\sqrt{(4x+5)(x-1)}\\\\2x=\sqrt{(4x+5)(x-1)}\\\\(2x)^2=(\sqrt{(4x+5)(x-1)})^2\\\\4x^2=(4x+5)(x-1)\\\\4x^2=4x^2+x-5\\\\0=x-5\\\\5=x\\\\\\Check:\\\sqrt{4(5)+5}-\sqrt{(5)-1}=\sqrt{(5)+4}\\\\\sqrt{25}-\sqrt{4}=\sqrt9\\\\5-2=3\ \checkmark$

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This is Extra Credit so its not a big deal but please help

Bezzdna [24]

Answer:

You earned $45.50 taking care of your neighbor's dog.

Step-by-step explanation:

Add 38.75 + 25. You get 63.75.

Subtract 63.75 - 18.25. That is how you get your answer. I hope this helps.

8 0

3 years ago

Compute the second partial derivatives ∂2f ∂x2 , ∂2f ∂x ∂y , ∂2f ∂y ∂x , ∂2f ∂y2 for the following function. f(x, y) = 2xy (x2 +

blsea [12.9K]

Answer with step-by-step explanation:

We are given that a function

$f(x,y)=2xy(x^2+y^2)^2$

Differentiate partially w.r.t x

Then, we get

$\frac{\delta f}{\delta x}=2y(x^2+y^2)^2+8x^2y(x^2+y^2)=(x^2+y^2)(2x^2y+2y^3+8x^2y)=2(5x^2y+y^3)(x^2+y^2)$

Differentiate again w.r.t x

$\frac{\delta^2f}{\delta x^2}=2(10xy)(x^2+y^2)+4x(5x^2y+y^3)=20x^3y+20xy^3+20x^3y+4xy^3=40x^3y+24xy^3$

Differentiate function w.r.t y

$\frac{\delta f}{\delta y}=2x(x^2+y^2)^2+2xy\times 2(x^2+y^2)\times 2y$

$\frac{\delta f}{\delta y}=(x^2+y^2)(2x^3+2xy^2+8xy^2)=2(x^2+y^2)(x^3+5xy^2)$

Again differentiate w.r.t y

$\frac{\delta^2f}{\delta x^2}=2(2y)(x^3+5xy^2)+20xy(x^2+y^2)=4x^3y+20xy^3+20x^3y+20xy^3=24x^3y+40xy^3$

Differentiate partially w.r.t y

$\frac{\delta^2f}{\delta y\delta x}=2(2y(5x^2y+y^3)+(x^2+y^2)(5x^2+3y^2))=10x^4+36x^2y^2+10y^4$

$\frac{\delta^2f}{\delta y\delta x}=10x^4+36x^2y^2+10y^4$ $\frac{\delta^2f}{\delta x\delat y}=2(2x(x^3+5xy^2)+(3x^2+5y^2)(x^2+y^2))=10x^4+36x^2y^2+10y^4$

$\frac{\delta^2f}{\delta x\delat y}=10x^4+36x^2y^2+10y^4$

Hence, if f(x,y) is of class $C^2$ (is twice continuously differentiable), then the mixed partial derivatives are equal.

i.e $\frac{\delta^2f}{\delta y\delta x}=\frac{\delta^2f}{\delta x\delta y}$

8 0

4 years ago

Savannah warks as a sales rep and receives 4.5% for every $140 she sells. How much commission will she receive?

Vladimir [108]

Answer:

C=4.5k

Step-by-step explanation:

an 25, 2018 — What is her rate of commission? ... Savanna works as a sales rep and receives $23.80 for every $140 she sells. ... 4.5K people helped ... Teresa makes 25% commission for every $100 she sells. ... Hilary earns a 22% commission on her sales and was paid $3498. ... Suppose she earns $750 next month.

1 answer

5 0

3 years ago

Read 2 more answers

HELP ME PLEASE!! <3

hammer [34]

Answer:

Y = 2x + 4

Step-by-step explanation:

The slope (rise / run) is 2 and the y-intercept is 4.

Hope this helps. Pls give brainliest.

5 0